ICF's

Insulating Concrete Forms (ICFs) continue to gain traction in concrete construction.  We get asked about cellular concrete for use in ICF's with increasing frequency.  "Will it work?" is the essence of the question.  Short answer, yes.  

With 110 to 120 pcf cellular concrete and the proper mix design, it is possible to get compressive strengths in the 3000 to 4000 psi range, which is more than sufficient for above ground residential construction. See earlier posts to the blog.  Note too that the mix design does not have to be exotic, but primarily a low water and higher than normal amount of cement.  Exact strength, as we have noted before, is dependent on local materials, batching techniques and mixing in addition to the mix design itself.  It is the responsibility of the user to do testing of a chosen mix design. 

At a recent demo day, we filled a section of ICF and later stripped away part of the form to view the fill we had achieved.  As you can see, it was pretty good, especially considering that we did not vibrate and did only a minimum amount of tapping on the forms. Considering the flowability that foam adds to concrete, these results are not surprising.  You'll add some (not a lot) of insulative value to the wall at this density. An R-value of .25 to .33 per inch would be typical at density of 110-120 pcf.

Conclusion.  You can provide a good quality job and save money too with cellular concrete!